/*
 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package javax.swing;


import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.beans.*;
import javax.swing.event.*;
import sun.awt.EmbeddedFrame;

/**
 * The KeyboardManager class is used to help dispatch keyboard actions for the
 * WHEN_IN_FOCUSED_WINDOW style actions.  Actions with other conditions are handled directly in
 * JComponent.
 *
 * Here's a description of the symantics of how keyboard dispatching should work atleast as I
 * understand it.
 *
 * KeyEvents are dispatched to the focused component.  The focus manager gets first crack at
 * processing this event.  If the focus manager doesn't want it, then the JComponent calls
 * super.processKeyEvent() this allows listeners a chance to process the event.
 *
 * If none of the listeners "consumes" the event then the keybindings get a shot. This is where
 * things start to get interesting.  First, KeyStokes defined with the WHEN_FOCUSED condition get a
 * chance.  If none of these want the event, then the component walks though it's parents looked for
 * actions of type WHEN_ANCESTOR_OF_FOCUSED_COMPONENT.
 *
 * If no one has taken it yet, then it winds up here.  We then look for components registered for
 * WHEN_IN_FOCUSED_WINDOW events and fire to them.  Note that if none of those are found then we
 * pass the event to the menubars and let them have a crack at it.  They're handled differently.
 *
 * Lastly, we check if we're looking at an internal frame.  If we are and no one wanted the event
 * then we move up to the InternalFrame's creator and see if anyone wants the event (and so on and
 * so on).
 *
 * @see InputMap
 */
class KeyboardManager {

  static KeyboardManager currentManager = new KeyboardManager();

  /**
   * maps top-level containers to a sub-hashtable full of keystrokes
   */
  Hashtable<Container, Hashtable> containerMap = new Hashtable<Container, Hashtable>();

  /**
   * Maps component/keystroke pairs to a topLevel container
   * This is mainly used for fast unregister operations
   */
  Hashtable<ComponentKeyStrokePair, Container> componentKeyStrokeMap = new Hashtable<ComponentKeyStrokePair, Container>();

  public static KeyboardManager getCurrentManager() {
    return currentManager;
  }

  public static void setCurrentManager(KeyboardManager km) {
    currentManager = km;
  }

  /**
   * register keystrokes here which are for the WHEN_IN_FOCUSED_WINDOW
   * case.
   * Other types of keystrokes will be handled by walking the hierarchy
   * That simplifies some potentially hairy stuff.
   */
  public void registerKeyStroke(KeyStroke k, JComponent c) {
    Container topContainer = getTopAncestor(c);
    if (topContainer == null) {
      return;
    }
    Hashtable keyMap = containerMap.get(topContainer);

    if (keyMap == null) {  // lazy evaluate one
      keyMap = registerNewTopContainer(topContainer);
    }

    Object tmp = keyMap.get(k);
    if (tmp == null) {
      keyMap.put(k, c);
    } else if (tmp instanceof Vector) {  // if there's a Vector there then add to it.
      Vector v = (Vector) tmp;
      if (!v.contains(c)) {  // only add if this keystroke isn't registered for this component
        v.addElement(c);
      }
    } else if (tmp instanceof JComponent) {
      // if a JComponent is there then remove it and replace it with a vector
      // Then add the old compoennt and the new compoent to the vector
      // then insert the vector in the table
      if (tmp != c) {  // this means this is already registered for this component, no need to dup
        Vector<JComponent> v = new Vector<JComponent>();
        v.addElement((JComponent) tmp);
        v.addElement(c);
        keyMap.put(k, v);
      }
    } else {
      System.out.println("Unexpected condition in registerKeyStroke");
      Thread.dumpStack();
    }

    componentKeyStrokeMap.put(new ComponentKeyStrokePair(c, k), topContainer);

    // Check for EmbeddedFrame case, they know how to process accelerators even
    // when focus is not in Java
    if (topContainer instanceof EmbeddedFrame) {
      ((EmbeddedFrame) topContainer).registerAccelerator(k);
    }
  }

  /**
   * Find the top focusable Window, Applet, or InternalFrame
   */
  private static Container getTopAncestor(JComponent c) {
    for (Container p = c.getParent(); p != null; p = p.getParent()) {
      if (p instanceof Window && ((Window) p).isFocusableWindow() ||
          p instanceof Applet || p instanceof JInternalFrame) {

        return p;
      }
    }
    return null;
  }

  public void unregisterKeyStroke(KeyStroke ks, JComponent c) {

    // component may have already been removed from the hierarchy, we
    // need to look up the container using the componentKeyStrokeMap.

    ComponentKeyStrokePair ckp = new ComponentKeyStrokePair(c, ks);

    Container topContainer = componentKeyStrokeMap.get(ckp);

    if (topContainer == null) {  // never heard of this pairing, so bail
      return;
    }

    Hashtable keyMap = containerMap.get(topContainer);
    if (keyMap == null) { // this should never happen, but I'm being safe
      Thread.dumpStack();
      return;
    }

    Object tmp = keyMap.get(ks);
    if (tmp == null) {  // this should never happen, but I'm being safe
      Thread.dumpStack();
      return;
    }

    if (tmp instanceof JComponent && tmp == c) {
      keyMap.remove(ks);  // remove the KeyStroke from the Map
      //System.out.println("removed a stroke" + ks);
    } else if (tmp instanceof Vector) {  // this means there is more than one component reg for this key
      Vector v = (Vector) tmp;
      v.removeElement(c);
      if (v.isEmpty()) {
        keyMap.remove(ks);  // remove the KeyStroke from the Map
        //System.out.println("removed a ks vector");
      }
    }

    if (keyMap.isEmpty()) {  // if no more bindings in this table
      containerMap.remove(topContainer);  // remove table to enable GC
      //System.out.println("removed a container");
    }

    componentKeyStrokeMap.remove(ckp);

    // Check for EmbeddedFrame case, they know how to process accelerators even
    // when focus is not in Java
    if (topContainer instanceof EmbeddedFrame) {
      ((EmbeddedFrame) topContainer).unregisterAccelerator(ks);
    }
  }

  /**
   * This method is called when the focused component (and none of
   * its ancestors) want the key event.  This will look up the keystroke
   * to see if any chidren (or subchildren) of the specified container
   * want a crack at the event.
   * If one of them wants it, then it will "DO-THE-RIGHT-THING"
   */
  public boolean fireKeyboardAction(KeyEvent e, boolean pressed, Container topAncestor) {

    if (e.isConsumed()) {
      System.out.println("Acquired pre-used event!");
      Thread.dumpStack();
    }

    // There may be two keystrokes associated with a low-level key event;
    // in this case a keystroke made of an extended key code has a priority.
    KeyStroke ks;
    KeyStroke ksE = null;

    if (e.getID() == KeyEvent.KEY_TYPED) {
      ks = KeyStroke.getKeyStroke(e.getKeyChar());
    } else {
      if (e.getKeyCode() != e.getExtendedKeyCode()) {
        ksE = KeyStroke.getKeyStroke(e.getExtendedKeyCode(), e.getModifiers(), !pressed);
      }
      ks = KeyStroke.getKeyStroke(e.getKeyCode(), e.getModifiers(), !pressed);
    }

    Hashtable keyMap = containerMap.get(topAncestor);
    if (keyMap != null) { // this container isn't registered, so bail

      Object tmp = null;
      // extended code has priority
      if (ksE != null) {
        tmp = keyMap.get(ksE);
        if (tmp != null) {
          ks = ksE;
        }
      }
      if (tmp == null) {
        tmp = keyMap.get(ks);
      }

      if (tmp == null) {
        // don't do anything
      } else if (tmp instanceof JComponent) {
        JComponent c = (JComponent) tmp;
        if (c.isShowing() && c.isEnabled()) { // only give it out if enabled and visible
          fireBinding(c, ks, e, pressed);
        }
      } else if (tmp instanceof Vector) { //more than one comp registered for this
        Vector v = (Vector) tmp;
        // There is no well defined order for WHEN_IN_FOCUSED_WINDOW
        // bindings, but we give precedence to those bindings just
        // added. This is done so that JMenus WHEN_IN_FOCUSED_WINDOW
        // bindings are accessed before those of the JRootPane (they
        // both have a WHEN_IN_FOCUSED_WINDOW binding for enter).
        for (int counter = v.size() - 1; counter >= 0; counter--) {
          JComponent c = (JComponent) v.elementAt(counter);
          //System.out.println("Trying collision: " + c + " vector = "+ v.size());
          if (c.isShowing() && c.isEnabled()) { // don't want to give these out
            fireBinding(c, ks, e, pressed);
            if (e.isConsumed()) {
              return true;
            }
          }
        }
      } else {
        System.out.println("Unexpected condition in fireKeyboardAction " + tmp);
        // This means that tmp wasn't null, a JComponent, or a Vector.  What is it?
        Thread.dumpStack();
      }
    }

    if (e.isConsumed()) {
      return true;
    }
    // if no one else handled it, then give the menus a crack
    // The're handled differently.  The key is to let any JMenuBars
    // process the event
    if (keyMap != null) {
      Vector v = (Vector) keyMap.get(JMenuBar.class);
      if (v != null) {
        Enumeration iter = v.elements();
        while (iter.hasMoreElements()) {
          JMenuBar mb = (JMenuBar) iter.nextElement();
          if (mb.isShowing() && mb.isEnabled()) { // don't want to give these out
            boolean extended = (ksE != null) && !ksE.equals(ks);
            if (extended) {
              fireBinding(mb, ksE, e, pressed);
            }
            if (!extended || !e.isConsumed()) {
              fireBinding(mb, ks, e, pressed);
            }
            if (e.isConsumed()) {
              return true;
            }
          }
        }
      }
    }

    return e.isConsumed();
  }

  void fireBinding(JComponent c, KeyStroke ks, KeyEvent e, boolean pressed) {
    if (c.processKeyBinding(ks, e, JComponent.WHEN_IN_FOCUSED_WINDOW,
        pressed)) {
      e.consume();
    }
  }

  public void registerMenuBar(JMenuBar mb) {
    Container top = getTopAncestor(mb);
    if (top == null) {
      return;
    }
    Hashtable keyMap = containerMap.get(top);

    if (keyMap == null) {  // lazy evaluate one
      keyMap = registerNewTopContainer(top);
    }
    // use the menubar class as the key
    Vector menuBars = (Vector) keyMap.get(JMenuBar.class);

    if (menuBars == null) {  // if we don't have a list of menubars,
      // then make one.
      menuBars = new Vector();
      keyMap.put(JMenuBar.class, menuBars);
    }

    if (!menuBars.contains(mb)) {
      menuBars.addElement(mb);
    }
  }


  public void unregisterMenuBar(JMenuBar mb) {
    Container topContainer = getTopAncestor(mb);
    if (topContainer == null) {
      return;
    }
    Hashtable keyMap = containerMap.get(topContainer);
    if (keyMap != null) {
      Vector v = (Vector) keyMap.get(JMenuBar.class);
      if (v != null) {
        v.removeElement(mb);
        if (v.isEmpty()) {
          keyMap.remove(JMenuBar.class);
          if (keyMap.isEmpty()) {
            // remove table to enable GC
            containerMap.remove(topContainer);
          }
        }
      }
    }
  }

  protected Hashtable registerNewTopContainer(Container topContainer) {
    Hashtable keyMap = new Hashtable();
    containerMap.put(topContainer, keyMap);
    return keyMap;
  }

  /**
   * This class is used to create keys for a hashtable
   * which looks up topContainers based on component, keystroke pairs
   * This is used to make unregistering KeyStrokes fast
   */
  class ComponentKeyStrokePair {

    Object component;
    Object keyStroke;

    public ComponentKeyStrokePair(Object comp, Object key) {
      component = comp;
      keyStroke = key;
    }

    public boolean equals(Object o) {
      if (!(o instanceof ComponentKeyStrokePair)) {
        return false;
      }
      ComponentKeyStrokePair ckp = (ComponentKeyStrokePair) o;
      return ((component.equals(ckp.component)) && (keyStroke.equals(ckp.keyStroke)));
    }

    public int hashCode() {
      return component.hashCode() * keyStroke.hashCode();
    }

  }

} // end KeyboardManager
